[stable31] fix(encryption): init filesystem before unshare hook

[hweihwang]

Summary

• Initialize filesystem for share owner before resolving file path during unshare hook
• Avoid null Filesystem view when running occ commands

• Resolves: [Bug]: Error executing ldap:show-remnants command with encryption enabled #49533

[blizzz]

@hweihwang thanks for the fix 🙏 Please set reviewers, labels and milestone when opening the PR. Could you provide some context on why this is opened against stable31, not master?

[hweihwang]

Thanks @blizzz

Likely cause:

• lib/private/Encryption/HookManager.php: postUnshared() calls Filesystem::getPath($params['fileSource']) before filesystem init
• lib/private/Files/Filesystem.php: getPath() uses self::$defaultInstance->getPath() with no null guard
• In occ context (no user session), filesystem not set up → $defaultInstance null → fatal

Seems only happen on <=31:

• stable28–stable31 use legacy hook path (HookManager::postUnshared wired via connectHook)
  • Ref: stable31/lib/base.php → connectHook(Share::class, 'post_unshare', HookManager::class, 'postUnshared')
• stable32+ replaces legacy hooks with event listener
  • Ref: stable32/lib/base.php → EncryptionEventListener::register()
  • Listener uses typed events + Update with setupManager->setupForUser() before work
  • No direct Filesystem::getPath() call in unshare handler; uses node object
  • Ref: stable32/lib/private/Encryption/EncryptionEventListener.php